From ae1a30eccd0a8e7643c82ed51d87f585dfdd4717 Mon Sep 17 00:00:00 2001
From: Kévin Le Gouguec <kevin.legouguec@airbus.com>
Date: Tue, 2 Jul 2019 09:47:19 +0200
Subject: Mise à jour de l'implémentation threshold
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/add_threshold/tweakey.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/src/add_threshold/tweakey.c b/src/add_threshold/tweakey.c
index 8f531d9..7822564 100644
--- a/src/add_threshold/tweakey.c
+++ b/src/add_threshold/tweakey.c
@@ -90,10 +90,11 @@ void tweakey_state_extract(
 
 typedef void (*matrix_multiplication)(const uint8_t x[LANE_BYTES], uint8_t y[LANE_BYTES]);
 
-static const matrix_multiplication ALPHAS[6] = {
+static const matrix_multiplication ALPHAS[7] = {
     _multiply_M,
     _multiply_M2,
     _multiply_M3,
+    _multiply_M4,
     _multiply_MR,
     _multiply_MR2,
     _multiply_MR3
@@ -102,16 +103,14 @@ static const matrix_multiplication ALPHAS[6] = {
 
 void tweakey_state_update(uint8_t TK_X[TWEAKEY_BYTES], uint8_t TK_Y[KEY_BYTES])
 {
-    /* Skip lane 0, as it is multiplied by the identity matrix. */
-
-    for (size_t j=1; j<TWEAK_LANES_NB; j++)
+    for (size_t j=0; j<TWEAK_LANES_NB; j++)
     {
         uint8_t *TKj_X = TK_X + j*LANE_BYTES;
 
         uint8_t TKj_old_X[LANE_BYTES];
         memcpy(TKj_old_X, TKj_X, LANE_BYTES);
 
-        ALPHAS[j-1](TKj_old_X, TKj_X);
+        ALPHAS[j](TKj_old_X, TKj_X);
     }
 
     for (size_t j=0; j<KEY_LANES_NB; j++)
@@ -124,7 +123,7 @@ void tweakey_state_update(uint8_t TK_X[TWEAKEY_BYTES], uint8_t TK_Y[KEY_BYTES])
         memcpy(TKj_X_old, TKj_X, LANE_BYTES);
         memcpy(TKj_Y_old, TKj_Y, LANE_BYTES);
 
-        ALPHAS[j-1 + TWEAK_LANES_NB](TKj_X_old, TKj_X);
-        ALPHAS[j-1 + TWEAK_LANES_NB](TKj_Y_old, TKj_Y);
+        ALPHAS[j + TWEAK_LANES_NB](TKj_X_old, TKj_X);
+        ALPHAS[j + TWEAK_LANES_NB](TKj_Y_old, TKj_Y);
     }
 }
-- 
cgit v1.2.3